If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Enjoy an ad free experience by logging in. Not a member yet? Register.

Yeah, this is an anonymous inner class. ActionListener itself is an interface, but since it is being invoked and the entire method set is being declared as a part of the class body, this is valid code. Prior to Java 8, it's also the closest thing we have to a closure in Java.
So effectively you create an unnamed instance and provide that as the argument. That particular instance can never be used again.